Cytomegalovirus infections are major problems for two classes of patients, the fetus and the immunosuppressed. A live CMV vaccine has been developed and tested successfully in normal male volunteers. An eventual goal of a CMV vaccine is to prevent intragestational primary infection in women. While the validity of this concept is being tested in epidemiologic studies, we wish to obtan data in non-pregnant women of child-bearing age with respect to humoral and cell-mediated response to CMV vaccine. The population we would study is one at increased risk of infection, namely pediatric and transplant nurses. This professional population is also one that can be easily followed for persistence of immunity and for the outcome of future pregnancies. In our previous grant we began to test CMV vaccine in renal transplant patients. The complementary goals of this research were to see if vaccination would protect the CMV-seronegative prospective recipients from disease and rejection and to see if the vaccine virus would become latent and be reactivated under conditions of immunosuppression. As described in our previous application, the first year consisted of an open trial, during which we gathered preliminary evidence for safety. Efficacy was not established, however, and is now the subject of a controlled trial that has begun during the second year of the original grant, and is expected to continue. Since most of the patients were given seropositive kidney or blood excreted virus, it will be most important to determine whether viruses excreted from patients are vaccine-related or are exogenous. This bears on the question of whether the vaccine strain is latent. We propose to answer this question by restriction endonuclease analysis of viral DNA purified from various CMV isolates. The results gained will solve two fundamental issues of attenuated CMV vaccine: Safety with regard to latency and reactivation, and efficacy with regard to protection against various strains.